Marko Kreen <marko(at)l-t(dot)ee> writes:
> What works:
> # select o.id from op o union all SELECT -1 order by id;
This is valid SQL.
> # select o.id from op o union all SELECT -1 order by o.id;
> ERROR: Relation 'o' does not exist
This is not valid SQL. For one thing, the table alias "o" is not
visible outside the first component SELECT.
Yes, I know 7.0 took it... but its handling of ORDER BY on UNION
was pretty darn broken.
regards, tom lane